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  #1  
Old Wed 01 October 2008, 12:47
vishnu
Just call me: vishnu
 
Coimbatore(TN)
India
Moved from another thread:

Hi Irfu,

Thats really nice. Working on the Impeller and want to see them in One piece before i start them. Nowadays i think you working a lot buddy. . . . . .

Vishnu
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  #2  
Old Wed 01 October 2008, 13:09
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Curious about your impeller design . . . . .

Only yesterday we compared two impellers that were giving very similar performance curves, but one needed double the Amps of the other!
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  #3  
Old Wed 01 October 2008, 13:46
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Here are the results:

Clipboard02.gif
305mm impeller . . . . . . . . . .. . 300mm impeller


Change attachment's .txt to .dxf to open with CAD:
Attached Files
File Type: txt extractor_impellers.txt (44.0 KB, 82 views)
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  #4  
Old Thu 02 October 2008, 01:07
javeria
Just call me: Irfan #33
 
Bangalore
India
Folk's thanks for the thumbs up, what me and Vishnu thought was to copy the impeller on the Bill Pentz site. Its the red one with dimensions marked on them. As a first try we will have a straight blades instead of curved ones, I dont think I have a photo here with me.

its on this link though

http://billpentz.com/woodworking/cyclone/Blower.cfm

G' the forward curved ( If I am right) are more efficient than the straight blades,

The cyclone I am building is a 18 inch dia one.

Today we are celebrating Eid, so work will start next on Monday and meanwhile I am finalizing BOM for my Mechmate and me and Vishnu have finished finalizing the electrical BOM.

RGDS
Irfan
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  #5  
Old Thu 02 October 2008, 01:10
javeria
Just call me: Irfan #33
 
Bangalore
India
G' did you use a anemometer to measure the CFM? I dont see the CFM figures / velocity figures
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  #6  
Old Thu 02 October 2008, 01:23
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
No, only used the pressure change across a known hole as a comparison. The actual CFM are of no interest to me.
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  #7  
Old Thu 02 October 2008, 01:33
javeria
Just call me: Irfan #33
 
Bangalore
India
ok, true as the CFM will depend on the ducting too.
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  #8  
Old Thu 02 October 2008, 07:14
Greg J
Just call me: Greg #13
 
Hagerman, New Mexico
United States of America
Gerald,

I know your test setup is very straight forward, but you lost me on the chart where you have "water sucked up hole". There is a 0 mm hole () and so forth with associated numbers (water column height ??).

In the past, I've taken a clear plastic tube and made a U-tube manometer. Water column height was the only variable.

Would you explain your test setup?

Greg

Edited: After rereading your reply to Irfan - Are you measuring pressure differential across an orifice plate (hole) ?
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  #9  
Old Thu 02 October 2008, 08:02
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Setup exactly as you have done it yourself (mechanical engineers are trained alike ). My wording was "water sucked up pipe" with the pipe being clear plastic dangling in a tub of water.

Actually, a cheap plastic funnel was held over the inlet of the fan, and the pipe/tube tight over the sharp end of the funnel. holes were then made in the conical part of the funnel to leak air into the fan.
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  #10  
Old Fri 03 October 2008, 12:46
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Here are 2 different dust collectors, both 2 HP, both with 1 micron bags. From their pictures and specs, they could be the equivalents of our Martlet and Huester:
"Martlet"
"Huester"
Here they are stocked by two different suppliers and they are claimed to be identical of each other's 2HP units. "They are all from China". The Jet brand could be one, or both, of those.
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  #11  
Old Fri 03 October 2008, 13:48
vishnu
Just call me: vishnu
 
Coimbatore(TN)
India
Dust collector Comparisions

Yes the the two units looks more or less identical, but i really doubt the suction capacity quoted at 1600 CFM, because of the size of the impeller and the motor capacity. I think 900 - 1000 CFM may be the actual results that can be obtained. I think for a one machine shop these units may be a good alternative to a cyclone. I have my own doubts whether it will achive the desired results obtained as equivalent to the cyclone dust evacuator. The DIY build of a cyclone will be in the range quoted in the retail price. i think its worth a try

Vishnu
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  #12  
Old Tue 15 September 2009, 11:01
DMS
Just call me: Sharma #9 India
 
Rajasthan
India
Dust Shoe

Following comment made in this post - moved to this thread

I am in process of building 2 HP cyclone.
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  #13  
Old Tue 15 September 2009, 19:01
DMS
Just call me: Sharma #9 India
 
Rajasthan
India
Your lasercut supplier could also do Martlet (curved fins) type Impeller? becoz these are better one.
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  #14  
Old Wed 16 September 2009, 05:30
javeria
Just call me: Irfan #33
 
Bangalore
India
Oh the impeller was just a copy from the Bill's website. if you want I can pass on the DXF.

btw do you have the dimensions of the martlet type fan?

RGDS
IRfan
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  #15  
Old Wed 16 September 2009, 07:01
javeria
Just call me: Irfan #33
 
Bangalore
India
Got it - I think the one I have made is performing superb - so no complaints and would certainly make one for others too. Getting a curved profile might be easy with the right tools but straight one is just much more easier!

RGDS
IRfan
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  #16  
Old Wed 16 September 2009, 07:07
DMS
Just call me: Sharma #9 India
 
Rajasthan
India
Thanks Gerald for dxf's
I copied dxf from this link,

Irfan,
I calculated 12" dia Impeller for my design from Bill's excel sheet, I prefer Martlet after seeing Gerald's comparision. But problem is where to get fins bent evenly ? I wonder if your laser cut parts suppliers could do it ?

Another option for impeller is I can finish it in wood, which can be supplied to foundry for Mold making where Aluminum alloy or Iron impeller could be molded.
Someone may suggest which is better Sheet metal Impeller of molded one ?
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  #17  
Old Wed 16 September 2009, 07:22
javeria
Just call me: Irfan #33
 
Bangalore
India
casting is a good way- but when at high speeds there is possibility of it disintegrating if there are some anomalies in the cast. better to go for sheet.

G' told me once that since in US motors are faster due to the higher frequency (60Hz) here its 50Hz - so I went in for a inch more on the dia.

If the backward curved fan works for me - then it should work for you too.

I got tired of trying to get to the best and went for one shown on the Bill's website!

RGDS
IRfan
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  #18  
Old Wed 16 September 2009, 07:39
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Just to be clear; "Martlet" is a local/UK trading house that buys goods in Asia and then put on their own label. Tomorrow Martlet can decide to put their name on the other fan, so the actual name means nothing about fan design.
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  #19  
Old Wed 16 September 2009, 07:40
DMS
Just call me: Sharma #9 India
 
Rajasthan
India
Wow that was quick

OK I go for 90 degree fins. Are you satisfied with performance and energy consumption ?
Where did you got laser cut impellers ? You remember mine charged higher, so no dealing with him.
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  #20  
Old Wed 16 September 2009, 07:57
javeria
Just call me: Irfan #33
 
Bangalore
India
Sharmaji - go for the backward curved fan - I will send you the drawings -

I put it on only when the cut is complete ( I am chicken to keep it on contineously with the GI case ). you can get them cut manually on oxy torch also - no need for laser cutting

just be sure to get it dynamically balanced.

I already sent it out! chk ur email
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  #21  
Old Wed 16 September 2009, 08:16
DMS
Just call me: Sharma #9 India
 
Rajasthan
India
Thanks

What the calculation basis of using 14 " I mean +10 Hz for + 2" ?
Mine motor is 50 Hz is 12 " ok for 2HP as per excel sheet?

What's the thickness of GI sheet you used?
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  #22  
Old Wed 16 September 2009, 08:54
javeria
Just call me: Irfan #33
 
Bangalore
India
oh 2 hp - I used a 3 hp one - cost difference only Rs 500 so.

i think i used the least thk GI sheet - used for manufacturing the AC ducts.

at 60Hz the fan spins faster than at 50Hz. so to compensate the loss in speed we increased the dia - again bhai I dont have anything to prove except the fact that its sucking thru 6mtrs of flex duct and 2mtrs of PVC pipe. and I have no complaints.

Just be sure to mount the motor properlly
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  #23  
Old Wed 16 September 2009, 09:44
DMS
Just call me: Sharma #9 India
 
Rajasthan
India
Thanks Irfan,

2 HP saves power also.
Awaiting till tomorrow for pic of hose.
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  #24  
Old Wed 16 September 2009, 09:51
javeria
Just call me: Irfan #33
 
Bangalore
India
no yaar 2 hp will pull more current if it gets loaded, once a motor is running the current consumption drops.

so a 3 hp will consume the same power as a 2 hp will once its started rotating, but a 3 hp will take it smoothly(does not heat up) due to the additional power capacity.

Read points 5 and 6 here http://billpentz.com/woodworking/Cyclone/Blower.cfm

RGDS
IRfan
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  #25  
Old Wed 16 September 2009, 10:22
DMS
Just call me: Sharma #9 India
 
Rajasthan
India
You are right !!!
Only if it gets loaded.
So I must balance HP, Hose dia, Inlet dia, outlet dia clearance and impeller size so that motor does not get loaded.

I have seen huge dia furnace blowers with lesser HP motor, smaller fins covered with plate to make pocket, having tremendous air pressure with smaller outlets.
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  #26  
Old Wed 16 September 2009, 10:37
javeria
Just call me: Irfan #33
 
Bangalore
India
ok - take your call dear
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  #27  
Old Wed 16 September 2009, 11:09
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
The reason for the heavy starting load is the energy needed to get that heavy "flywheel" spinning up to speed. The thicker the material used in the impeller, the heavier the initial current draw. A bigger motor gives spare torque to reduce the time of the high current.
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  #28  
Old Thu 17 September 2009, 18:48
DMS
Just call me: Sharma #9 India
 
Rajasthan
India
Irfan,

plz post photo.
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  #29  
Old Fri 18 September 2009, 00:37
javeria
Just call me: Irfan #33
 
Bangalore
India
sent -
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  #30  
Old Sun 08 November 2009, 09:59
Marinus
Just call me: Marinus
 
Pretoria
South Africa
Is a cyclone better that a conventional dust extractor?
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